Sir
Quality of wires, does matter rather then thickness, a good quality branded wiring like Pioneer, stinger and fusion 12/10 Gauge is much better then a thick local wiring.
You need a lower gauge (thicker) wiring only, if you are feeding a high power AMP/SUB, or for ground wiring.
Please also make sure that what they @splfanatic, @smartboy_am have suggested is done.
Always look at the resistance and conductive capacity a wire can produce, before buying any electrical wire and match it with your application (equipment).
The wire should not be of lower gauge (thick) or you will spend more money, nor it will be of higher gauge (thin) or you will have a risk for your equipment, they both should be perfectly matched.
Good branded wires keep EMI influence and noise levels at safe positions.
Regards